Papakura to Drury enabling works allow for SH1 widening

Groundfix was engaged by Fulton Hogan on the Papakura to Drury motorway extension project, completing an enabling works package to allow widening of SH1.

Scope involved the removal of the existing abutment, and stabilisation of the cut face with 10m soil nails and shotcrete. Works were staged to prevent comprising the stability of the bridge.

Four lift stages were required; excavation of a 1.5m lift, installation and load testing of a row of soil nails, installation of drainage & reinforcing steel, and application of shotcrete (sprayed concrete). These steps are then repeated for the following lift. The excavation included the removal of a large concrete beam from underneath the abutment and the careful deconstruction and removal of polystyrene blocks that were used as backfill in the original construction of the abutment.

Self-drilled soil nails were selected for the works, due to the instability of backfill material used in the construction of the bridge. A total of 104x10m long R32 DYWIDAG hollow bar soil nails were installed.

The full scope of enabling works (excavation, concrete cutting, drilling / soil nailing, load testing, steel fixing and shotcreting) were completed in-house.

Groundfix led the full package of works and used our wide range of skills to minimise downtime and risk, compared to engaging multiple subcontractors.

CAPABILITIES
Shotcrete/ sprayed concrete
Slope stabilisation and rock fall protection
Soil nails